bcma: reject PCI cards in bcma.

bcma currently only supports PCIe cards and no PCI cards, reject them
if we find them. I have never heard of any PCI card using the AI bus
(bcma), all of them are using ssb instead.

Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>
Signed-off-by: John W. Linville <linville@tuxdriver.com>